added toOption function to Event. Added issues 0005 to 0010
started with redesign of SF
reimplemented most methods of StF
reimplemented signal functions
reimplemented and passed most tests
finished tests for SF and EF applicative
all tests pass; fixed bugs in merge and upon combinators
renamed SfT to RF
added and tested Cache class; some documentation in dire.package
updated reactor to use Cache class in order to store results of cached signal functions
more code reuse in Reactive
Reactor now extends DireActor to maximized code reuse
redesigned data sinks
prepared redesign
started reimplementing using Event only
reimplemented data sink and most functions on SF
finished with reimplementation; tests still missing
updated todo
all tests written so far pass
implemented issue 0011